FIG. 9 shows a front left door of a passenger vehicle, viewed from the vehicle exterior side. The door 50 is provided with a door panel 51 and a door frame 52 positioned on top of the door panel 51, and the area which is surrounded by the upper edge of the door panel 51 and the inner edge of the door frame 52 is defined as a window opening 53. A door glass 54 is installed in the window opening 53 to be movable up and down.
As shown in FIG. 10, a glass guide portion 55 having a U-shaped (concave-shaped) cross section which is open toward the window opening 53 is formed on the inner periphery of the door frame 52, and an outer peripheral edge of the door glass 54 enters the glass guide portion 55 when the door glass 54 closes the window opening 53. A glass run 56 made of an elastic material is fitted in and held by the glass guide portion 55, and the edge of the door glass 54 which has entered the glass guide portion 55 is elastically held by lips 56a and 56b of the glass run 56 therebetween from the vehicle interior side and the vehicle exterior side, respectively. Note that FIG. 10 shows the lips 56a and 56b in a free state, in which the lips 56a and 56b are in noncontact with the door glass 54; the lips 56a and 56b are elastically deformed in directions away from each other when contacting the door glass 54. The glass guide portion 55 is provided on the vehicle interior side with a side wall portion 55a which supports the lip 56a and provided on the vehicle exterior side with a side wall portion 55b which supports the lip 56b on the vehicle exterior side.
The door frame 52 is provided with an upper sash 57 which forms the upper edge of the door and a side sash 58 which extends upwards from the rear of the door panel 51. Although a cross-section structure of the side sash 58 is shown in FIG. 10, the upper sash 57 also has a similar door glass holding structure composed of the glass guide portion 55 and the glass run 56. In addition, it is sometimes the case that the width for holding the door glass 54 by the glass guide portion 55 (the amount of overlapping between the door glass 54 and the side wall portions 55a and 55b) in the upper sash 57 and the width for holding the door glass 54 by the glass guide portion 55 (the amount of overlapping between the door glass 54 and the side wall portions 55a and 55b) in the side sash 58 are made different from each other. For instance, in the side sash 58, it is sometimes required to enhance the retention capability by increasing the width for holding the door glass by the glass guide portion 55 so as to prevent the door glass 54 from vibrating and rattling in a half-open state, whereas in the upper sash 57 it is sometimes required to reduce the width for holding the door glass by the glass guide portion 55 (especially the side wall portion 55b) so as to narrow the width of the design portion outwardly exposed.
To satisfy such demands, in Patent Literature 1, a frame portion of the upper sash and a frame portion of the side sash are formed as separate members having mutually different glass-holding widths in the glass guide portion and joined to each other at a corner portion of the door frame which corresponds to the boundary between the upper sash and the side sash.